EP0928394B1

EP0928394B1 - Device for filtering and cooling

Info

Publication number: EP0928394B1
Application number: EP97935969A
Authority: EP
Inventors: Stig-Erik Johannesson
Original assignee: Volvo Lastvagnar AB
Current assignee: Volvo Truck Corp
Priority date: 1996-09-24
Filing date: 1997-08-21
Publication date: 2003-01-29
Anticipated expiration: 2017-08-21
Also published as: EP0928394A1; US6216772B1; SE509759C2; DE69718801D1; DE69718801T2; SE9603483L; BR9712837A; WO1998013644A1; SE9603483D0

Abstract

The present invention relates to a device for filtration and cooling of a liquid medium which is guided through a lubricated component (1), said device containing an inlet (8) for supply of said medium to a filtering component (12) which defines a cavity (26) to which filtered medium is guided, a cooling device (10) and an outlet (31) for supply of said medium back to said component (1). The invention is characterized in that said cooling device (10) is arranged downstream of said cavity (26), said cavity (26) being connected to the cooling device (10) and said cooling device (10) being connected to said outlet (31). By means of the invention, an improved device is provided for filtration and cooling of a liquid medium, in particular oil for a gearbox in a motor vehicle.

Description

TECHNICAL FIELD:

The present invention relates to a device for filtration and cooling of a liquid medium, according to the preamble of appended claim 1. The invention is particularly intended for use in the field of motor vehicles, in particular for filtration and cooling of oil that is utilized for lubrication of a gearbox. (WO 96/26353).

BACKGROUND OF THE INVENTION:

In a manner which is well known, oil is used in the field of motor vehicles for lubrication of for example the vehicle gearbox. For purification of the oil, an oil filter is normally used, through which the oil is caused to flow. During the filtration, contaminants (for example in the form of solid particles) in the oil are separated from the liquid phase. The reason for this is that the oil is caused to pass a porous layer in the oil filter, by means of which the contaminants will remain in said layer.
For filtration of oil in the gearbox of a heavy goods vehicle, a so-called "spin-on-filter" is normally used, which is normally arranged on the outside of the gearbox and is connected to inlets and outlets for the oil that flows through the gearbox. The filter is constructed as a container, normally of sheet-metal, which contains an oil-filtering element in the form of a porous filtering material, through which the oil is fed. When the filter has been used for a certain time, it must be renewed, wherein the entire spin-on-filter is discarded and exchanged for a new filter. In this connection, the term "spin-on" refers to the fact that the filter-exchange is carried out by means of the filter being provided with a threaded portion, by means of which the filter can be screwed on directly during an exchange.
Furthermore, as regards lorries, there is in some cases a need for cooling of the oil in the gearbox as well. In particular such a need arises in countries having a warm climate, or in places where driving takes place in exceptionally exposed environments, for example in mines. According to known technique, the cooling of the oil is in this case carried out by means of an oil cooler being mounted between the gearbox pump and the oil filter. The oil that is utilized in the gearbox will in this case be fed through the oil cooler, where the oil is cooled down, whereupon the oil is filtered in the oil filter. To this end, the oil cooler is provided with connections for an inlet and an outlet for a suitable refrigerant, for example water. In this case, the oil that is passing the cooler can be cooled due to the fact that cooling water is flushed through the cooler.
Although today's oil filters normally operate satisfactorily, they still have certain drawbacks. For example, the known type of spin-on-filter is not suitable to use due to environmental reasons, since the entire filter, including its casing, has to be discarded when the filter must be renewed.
An additional drawback as regards the known technique is that the oil that is fed into the filter is relatively cold, which is due to the fact that it has passed the cooler immediately before. Since cold oil is comparatively viscous, this will provide an inferior flow through the oil filter part. Furthermore, the oil that is fed through the oil cooler is contaminated, i.e. it is supplied directly from the gearbox and contains contaminants, for example in the form of particles. There is a risk of these contaminants blocking the oil cooler, which can result in costly and unwanted breakdowns.

SUMMARY OF THE INVENTION:

The object of the present invention is thus to provide an improved device for cooling and filtration of a liquid medium, particularily oil that is utilized in a motor vehicle, wherein the above-mentioned drawbacks are eliminated. Said object is accomplished by means of a device as initially mentioned, the characterizing features of which will be apparent from the appended claim 1.
The invention is intended to be used for filtration and cooling of a liquid medium which preferably, but not exclusively, can be constituted by lubricating oil for a lubricated component, for example a gearbox. The invention comprises an inlet for supply of said medium to a filtering component, which defines a cavity to which filtered medium is guided. The invention also comprises a cooling device and an outlet for supply of said medium back to said component. A basic principle for the invention is that the cooling device is arranged downstream of said cavity, wherein the cavity is connected to the cooling device and the cooling device is connected to the outlet. Due to the fact that the cooling device is arranged downstream of the filtering component, the entire amount of liquid medium will be filtered before it reaches the cooling device. Since the medium is filtered when it flows through the filtering device, there is basically no risk of contaminants accumulating and blocking the cooling device.
An additional advantage of the invention is that it provides an improved flow through the filtering component, which is due to the fact that the liquid medium is normally warm when it is fed out from the gearbox and flows towards the filtering component. This will in turn provide an improved flow and an increased percolation through the filtering component, which in turn will result in a more effective filtration.
According to a certain embodiment of the invention, the filtering component is arranged as a detachable part in a filter protection, i.e. the filtering component constitutes an insertion filter. This implies an environmental advantage, since only the filtering component, which for example can be produced of paper, has to be discarded in connection with a filter-exchange.
Advantageous embodiments will be apparent from the appended dependent claims.
In this connection, the term "filtering component" refers to the component, for example in the form of a filtering paper, that is arranged inside a sleeve-like filter protection and through which the contaminated medium is supplied. The term "filter unit" refers to the component that consists of the filtering component and said filter protection and that is adapted for mounting in the component in which the medium is used, for example for lubrication.

BRIEF DESCRIPTION OF THE DRAWINGS:

The invention will be described in detail in the following with reference to the annexed drawing, which is a cross-sectional view of a device according to the present invention.

PREFERRED EMBODIMENT:

Fig. 1 shows a cross-sectional view of a device according to the invention, which, according to the preferred embodiment, constitutes a combined filter- and cooling device for a liquid medium. The invention is primarily intended for use in connection with a motor vehicle, for example a heavy goods vehicle, for filtration and cooling of oil in the vehicle gearbox. Thus, the drawing shows the casing 1A of the gearbox 1. An oil pump 2 is arranged in the interior of the gearbox, by means of which oil pump oil can be supplied to the device according to the invention. The oil is used for lubrication of components forming part of the gearbox, said lubrication being carried out in a manner which is previously known and therefore will not be described here in detail.
The oil pump comprises a pump body 3, a pump cover 3A and a pump axle 4, which is rotatably arranged in the pump body 3. In a known manner, the pump axle 4 is driven by being connected to a driving axle 5, which in turn is driven by an axle in the gearbox and ultimately by the vehicle motor (not shown). Also, the oil pump 2 contains a pump element in the form of a gear wheel 6 which is arranged on the pump axle 4 and which also drives a ring-shaped gear wheel. Many other types of pumps are possible. The oil is supplied via an inlet 7 and pumped by means of the oil pump 2 in the direction of a chamber 8 that is arranged downstream of the pump element 6.
The device according to the invention contains two main components, namely a filter unit in the form of an oil filter 9 and an oil cooler 10. For mounting of said components on a gearbox, the casing 1A is designed so that it forms an opening. The filter unit 9 is designed having an essentially tubular filter protection 11 which supports a similarily tubular filtering component 12 which is constructed of a filtering material, preferably filtering paper which, according to known manner, is designed for separation of particles that are present in percolating, contaminated oil. The filtering component 12 is inwardly delimited by a stay tube 13 which preferably is constituted by a perforated tube, which for example is made of plastics or steel and is utilized to fix the filtering component in its intended form.
Furthermore, the end of the filter protection 11 that faces towards the gearbox, is designed as a sleeve, the shape of which corresponds to a circular edge 14 on the pump cover 3A. Also, a circular seal 15 is arranged between the end part of the filter protection 11 and said edge 14. Furthermore, the filter protection 11 is designed having a peripheral flange 16, which is intended to bear against the outside of the casing 1A when the filter- and the cooling device according to the invention is in its mounting position.
The oil cooler 10 according to the invention is arranged at the end of the filter protection 11 that is not facing towards the gearbox 1. For this reason, this end of the filter protection 11 is designed having a protruding part in the form of a tubular support sleeve 17, which extends through the oil cooler 10. As is apparent from the drawing, the support sleeve 17 is hollow. The outermost end part of the support sleeve 17 is provided with threads which cooperate with a nut 18, which thus may be used to screw the oil cooler 18 together with the filter unit 9. Outermost at the nut 18, a plug 19 is arranged. Furthermore, a seal 20 is arranged between the nut 18 and the oil cooler 10.
The oil cooler 10 is previously known and comprises a fine-meshed net of channels (not shown), through which a cooling medium, preferably water, can be supplied. For supply of this cooling medium, the oil cooler 10 is provided with a connection 21 which constitutes an inlet for feeding the cooling medium into the oil cooler. This connection 21 is connected to a (not shown) cooling water container or coolant supply, which is arranged in connection with the gearbox. The oil cooler 10 also contains an additional (not shown) connection, which constitutes an outlet for feeding the cooling water out of the oil cooler 10 and back into the water container or the coolant supply.
By means of the pump 2, the oil that is utilized to lubricate the gearbox is fed from the inlet 7 and towards the chamber 8. When the pump 2 is in operation, there is a risk of an abnormally high pressure in the chamber 8. This may for example be the case during cold starts, when the oil is still cold and thus viscous. During too high pressures in the chamber 8, there is a risk that damages occur to the pump 2. In order to reduce the risk of such damages, an overflow valve 22 is arranged in connection with the pump 2. The valve 22 comprises a valve piston 23 which is movable in its longitudinal direction and which, in its natural state, blocks an opening 24 which connects the chamber 8 with the oil inlet 7. By means of a spring element 25, the valve piston 23 is biased to assume this state. The valve 22 is adapted so that it opens, i.e. is removed, at a predetermined pressure, for example 4 bar, whereby the opening 24 is no longer blocked. This results in the oil in the chamber 8 being guided back to the inlet 7 via the channel 33, which in turn results in the oil being rapidly warmed up, which is due to the fact that the oil is pumped around in this manner. By means of the increase of the oil temperature, the flow- ability of the oil also increases. The predetermined pressure, at which the valve piston 23 exposes the opening 24, can preferably be adjusted by means of the choice of spring element 25.
The filtration and the cooling of oil according to the invention will now be described with reference to the drawing. Oil having a normal pressure and which is fed in through the chamber 8, will be guided further into the filter unit 9. Here, the oil will pass through the filtering component 12 which collects particles and other contaminants in the oil. The oil which in this manner is filtered, will pass out towards an essentially tubular cavity 26 in the interior of the filtering component 12. Here, the oil is fed in the direction that is indicated by means of the arrows in the drawing.
The filtered oil, which thus has passed the oil-filtering component 12, is further fed in the direction of the end of the cavity 26 that is fales from the gearbox. Due to the fact that the filter protection 11 is provided with at least one, though preferably two or more, bored-out channels 27 and 28, respectively, which connect the filter protection 11 with the oil cooler 10, the oil will be fed into the oil cooler 10. Furthermore, the oil cooler 10 is designed having an essentially ring-shaped chamber 29 into which the oil is fed. The chamber 29 is arranged around the support sleeve 17 of the filter protection 11. Furthermore, the part of the oil cooler 10 which is arranged downstream is designed so that the oil is guided towards the support sleeve 17, which is provided with at least one, though preferably a plurality of, openings 30 which allow oil to pass towards the interior of the support sleeve 17, according to what is indicated by means of an arrrow in the drawing.
The interior of the support sleeve 17 is connected to an outlet 31 for oil, i.e. an outlet which guides the oil back into the gearbox and towards its different points of lubrication. The connection between the interior of the support sleeve 17 and the outlet 31 is constituted by a separate connection component in the form of an elongated tube 32. The tube 32, which preferably has a circular cross-section, is mounted so that one of its ends is arranged inside the support sleeve 17 and the other end is arranged in the pump body 3, whereupon a tight connection is obtained between the tube 32 and the interior of the support sleeve 17, and between the tube 32 and the outlet 31, respectively. It is apparent from the drawing, that the tube 32 extends through the inner cavity 26 inside the filtering component 12.
By means of the invention, the filtered oil that is present in the cavity 26 will be forced against the oil cooler 10 via the holes 27, 28, in which oil cooler the oil is cooled down. Furthermore, the oil is fed via the holes 30 into the interior of the support sleeve 17 and further into the tube 32. In this manner, the oil will be guided through the tube 32 and towards the outlet 31, whereupon the oil is guided further through the gearbox in a manner which is not shown.
Due to the fact that the oil cooler 10 is arranged downstream of the filtering component 12, the entire amount of oil will at first be filtered and then cooled down. This results in that the oil that is filtered is warm, which results in an improved flow through the oil-filtering component. Furthermore, contaminants will be separated from the oil before the oil reaches the oil cooler 10, which reduces the risk of the oil cooler being blocked due to accumulation of particles.
Since the filter unit 9 primarily only contains the filtering component 12 and the filter protection 11, the filter unit also can be made environmentally advantegeous. During exchange of an oil filter in a vehicle, the oil cooler 10 is initially removed, whereupon the filter protection 11 is removed from its place in the gearbox casing 1A. Thereafter, the filtering component 12, which for example is constituted by filtering paper, is removed and discarded. This will result in a minimum of ecologically harmful waste.
The invention is not limited to the embodiment which is described above, but may be varied within the scope of the appended claims. For example, the invention may be utilized in different types of vehicles, and in principle also in applications which are not related to vehicles, but where it is desirable to filter and cool of a liquid medium intended for a lubricated component.
Furthermore, the invention may be constructed so that the cavity, through which the oil is fed before it reaches the oil cooler 10, can be arranged inside as well as outside the filtering component 12, provided that the oil from the cooling device is fed to the outlet 31 through the cavity via a connection element.

Claims

Device for filtration and cooling of a liquid lubricating medium for a lubricated component (1), said device comprising an inlet (8) for supply of said medium, a filtering component (12) which defines downstream a cavity (26) to which filtered medium is guided, an outlet (31) for supply of said medium back to said component (1) and a cooling device (10), said cooling device (10) being arranged downstream of said cavity (26), wherein the cavity (26) is connected to the cooling device (10) and the cooling device (10) is connected to said outlet (31), characterized in that the cooling device (10) is connected to the outlet (31) via a connection component (32) which connects to the interior of the cooling device (10) and to said outlet (31) and which extends through said cavity (26).
Device according to claim 1, characterized in that said connection component (32) is constituted by a detachable tube.
Device according to any of the preceding claims, wherein the filtering component (12) is supported in a filter protection (11) which is adapted for mounting in connection with said component (1), characterized in that the cooling device (10) is adapted for mounting on the end of the filter protection (11) that faces away from the component (1), wherein the filter protection (11) comprises at least one opening (27, 2B) for passage of said medium from said cavity (26) to said cooling device (10).
Device according to claim 3, characterized in that said filter protection (11) comprises an essentially tubular part (17) that extends into the cooling device (10), wherein said part (17) comprises at least one opening (30) for passage of said medium from the cooling device (10) and to the interior of said part (17).
Device according to claim 4, characterized in that said connection element (32) is adapted for detachable attachment at the interior of said tubular part (17) and at said outlet (31).
Device according to any of the preceding claims, characterized in that said filtering component (12) is constituted by an element that is detachable from the filter protection (11).
Device according to any of the preceding claims, wherein said inlet (8) is adapted for supply of said medium from a connection (7), from which the medium is pumped by means of a pump element (4, 5, 6), characterized in that the inlet (8) is provided with a passage (24) for removal of said medium, wherein said passage (24) can be closed by means of a valve arrangement (22) that is pressure actuated, whereupon said valve arrangement adopts a position in which the passage (24) will be opened when the pressure in said inlet (8) exceeds a predetermined value.
Device according to claim 7, characterized in that said passage (24) is connected to said connection (7).
Gearbox for a vehicle, said gearbox comprising a device for filtration and cooling of a liquid medium according to any of the preceding claims, wherein said medium is constituted by oil flowing in the gearbox.